Scattergram graph relationship

Describing scatterplots (form, direction, strength, outliers) (article) | Khan Academy

scattergram graph relationship

A scatterplot is a type of data display that shows the relationship between two numerical variables. Each member of to scatterplots. Constructing a scatter plot . Scatter plots are similar to line graphs in that they use horizontal and vertical axes to plot The relationship between two variables is called their correlation. Scatter Plot (also called scatter diagram) is used to investigate the possible relationship between two variables that both relate to the same event. A straight line.

If no dependent variable exists, either type of variable can be plotted on either axis and a scatter plot will illustrate only the degree of correlation not causation between two variables.

scattergram graph relationship

A scatter plot can suggest various kinds of correlations between variables with a certain confidence interval. For example, weight and height, weight would be on y axis and height would be on the x axis. Correlations may be positive risingnegative fallingor null uncorrelated.

Scatter plot - Wikipedia

If the pattern of dots slopes from lower left to upper right, it indicates a positive correlation between the variables being studied. If the pattern of dots slopes from upper left to lower right, it indicates a negative correlation.

scattergram graph relationship

A line of best fit alternatively called 'trendline' can be drawn in order to study the relationship between the variables. An equation for the correlation between the variables can be determined by established best-fit procedures. For a linear correlation, the best-fit procedure is known as linear regression and is guaranteed to generate a correct solution in a finite time.

scattergram graph relationship

No universal best-fit procedure is guaranteed to generate a correct solution for arbitrary relationships. A scatter plot is also very useful when we wish to see how two comparable data sets agree to show nonlinear relationships between variables. A perfect negative correlation is given the value of If there is absolutely no correlation present the value given is 0.

What is a Scatter Plot and When to Use It

The closer the number is to 1 or -1, the stronger the correlation, or the stronger the relationship between the variables. The closer the number is to 0, the weaker the correlation.

So something that seems to kind of correlate in a positive direction might have a value of 0. An example of a situation where you might find a perfect positive correlation, as we have in the graph on the left above, would be when you compare the total amount of money spent on tickets at the movie theater with the number of people who go.

What is a Scatter Plot and When to Use It

This means that every time that "x" number of people go, "y" amount of money is spent on tickets without variation. An example of a situation where you might find a perfect negative correlation, as in the graph on the right above, would be if you were comparing the amount of time it takes to reach a destination with the distance of a car traveling at constant speed from that destination.

scattergram graph relationship

On the other hand, a situation where you might find a strong but not perfect positive correlation would be if you examined the number of hours students spent studying for an exam versus the grade received. This won't be a perfect correlation because two people could spend the same amount of time studying and get different grades.

scattergram graph relationship

But in general the rule will hold true that as the amount of time studying increases so does the grade received. Let's take a look at some examples.